Stereoscopic plotter



April 23, 1953 N. B. PLATT 2,636,416

STEREOSCOPIC PLOTTER Filed Dec. 29, 1950 4 Sheets-Sheet l Z3 Ivg .1% Jay11.?l

ATTDRNEYS April 28, 1953 N. B. PLATT sTEREoscoPIc PLOTTER 4 Sheets-Sheet2 Filed Dec. 29, 1950 INVENTOR. /Z/dffza/z/i ATTD RN EYS April 28, 1953N. B. PLATT sTEREoscoPIc PLOTTER Filed Dec. 29, 1950 4 Sheets-Sheet 3 R.m m m ATTE] R N EYS STEREOSCOPIC PLOTTER `4 Sheets-Sheet 4 Filed Dec.29, 1950 JI III/lll ZI, a.. 12H? ff if 0 4 i /lg j W 7 ya@ 7@ 22.93 221k1,9? 3 l 115g' Il? 7 77 7^ i 5f Ax TRNEYS Patented Apr. 28, 1953 UNITEDSTATES ,ATENT OFFICE 3 Claims.

This invention relates to topography, and more particularly to anapparatus for producing accurate maps from aerial photographs.

The object of the invention is to provide an apparatus which includes apair of adjustable tables, each supporting an aerial photograph ofterrain, there being a movable tracing instrument for recording on a mapall points having the same elevation.

Another object of the invention is to provide an apparatus whereby, bythe simultaneous use of both eyes of the operator, details can beaccurately transferred from a pair of aerial photographs to the mapbeing made.

Still another object of the invention is to provide amap-makingapparatus wherein the tables which support the aerialphotographs can be tipped or adjusted in order to provide for parallaxadjustment, the parts of the apparatus being adjustable whereby aparallax free virtual model is produced, the apparatus enabling theoperator to draw planimetrie details in their true positions.

Another object of the invention is to provide a map-making apparatuswhich is relatively inexpensive to manufacture.

Other objects and advantages will be apparent during the course of thefollowing description.

In the accompanying drawings forming a part of this application, inwhich like numerals are used to designate like parts throughout thesame:

Figure 1 is a front elevational View of the mapmaking apparatusconstructed according to the present invention, with parts broken awayand in section;

Figure 2 is an end elevational View of the apparatus of the presentinvention;

Figure 3 is a top plan view of the apparatus of the present invention;

Figure 4 is a horizontal sectional view taken through the apparatus andlooking down on the table;

Figure 5 is a side elevational view of the combination tracinginstrument and light source;

Figure 6 is a sectional View taken on the line 6-6 of Figure 5;

Figure 7 is a top plan view of the assembly of,

Figure 5;

Figure 8 is a vertical sectional view taken through the combinationtracing instrument and light source;

Figure 9 is a sectional view taken on the line 9 9 of Figure 5;

Figure l0 is a sectional view taken on the line lll--i of Figure 2;

Figure 1l isa sectional view taken on the line l i-| I of Figure 2v;

Figure 12 is a sectional view taken on the line E2`-i2 of Figure 11;

Figure 13 is a sectional view taken on the line l3-I3 of Figure 123;

Figure 14 is a face view of one of themounting means for the eye piecemirrors;

Figure 15 is a sectional View taken on the line IE-l of Figure 14;

Figure 16 is a sectional View taken on the line Iii-I6 of Figure 14;

Figure 17 is a longitudinal sectional view taken through the eye piecemounting and showing partsin section and certain parts separated forclarity; f i Figure 18 is an elevational view of one of the body pieces;

Figure 19 is an elevational View of one oi the support pieces;

Figure 20 is an elevational View of vone of the mirror-holding pieces;

Figure 21 is a sectional view taken on the line 2I--2l of Figure 14.

Referring in detail to the drawings, the numeral il! designates ahorizontally disposed table which includes a web 4I, Figures 1 and 4,Aand extending from the web 4i is a pair of spaced, parallel arms d2.'For supporting the table 4Q, a plurality of vertically disposed, spaced,parallel leg assemblies 43 are provided. Each of the leg assemblies 43includes a hollow stem lliv that has its upper vend extending through anopening l5 in the table 46, and the upper end of the .sleeve i4 issecured to the table by suitable securing elements, such as rivets 46.

Adj ustably mounted in each of the sleeves 4 is an elongated bushing 4l,the bushing 41 being maintained immobile in its various adjustedpositions within the sleeve M by suitable set screws t8, Figure l. Thebushing 47 is provided with' an interiorly threaded socket 49, andarranged in engagement with the socket 49 is an exteriorly threaded stem50. A knurled knob 52 is secured to the stem 5i) adjacent its lowerendfor rotating the latter, and a foot 5l is secured to the bottom-ofthe stem 5i] for engaging the floor or other surface. Thus, by adjustingor rotating the knob 52, or by adjusting the position of th bushing 4l,the height of the leg assemblies 43 can be adjusted or varied asdesired. Extending upwardly from the web il and secured thereto is apair of spaced, parallel, vertioally disposed standards 53, Figure 3.The lower ends of the standards 55 are maintained connected to the web-4I of the table 43 by suitable nuts 54, Figure 1. Mounted on the upperends of the pair of standards 53 are clamps 55, and a pairv ofhorizontally disposed, spaced, parallel, cylindrical bars 56 aresupported by the clamps 55. The bars 55 serve to support a pair ofspaced brackets 51. Y

Extending forwardly from each of the brackets 51 is a horizontallydisposed post 58, each of the posts 58 being provided with a threadedend 59 which is arranged in threaded engagement with the bracket 5i. Asuitable nut 6l! is arranged inV engagement with the threaded end 5S,whereby the posts 58 can'be adjusted or rotated. A stereo-v scopicmirror is connected to each of the posts 58. Thus, the numeral 6Idesignates a plate which is connected to the post 58 by a suitable bolte2, Figure 1, and a knurled knob or nut 63 is arranged in engagementwith the bolt 62 for maintainingv these parts in assembled relation.Arranged :in spaced` relation below each of the plates 6I is a bodymirror Ell. A plurality of spaced, parallel bolts 5 serve to connect themirror G4 to the plates 6I, and a knurled knob 66 serves to main-` tainthese parts in adjusted or assembled relation. A coil spring 61 iscircumposed upon each of the bolts 55 between the plates SI and themirror 64. By rotating or turning the -knob 66, a very accurate`adjustment of the mirror 64 can be effected or accomplished.

A means is provided Afor adjustably sumiorting a pair of transparent eyepiece mirrors 88 on the machine. This lmeans comprises a stub shaft 69Which-nasa threaded end arranged in threaded engagement with the frontend of the clamp An adjusting nut 'II is arranged in engagement with thethreaded end 1b, 4li'gure 3., and secured to the front end of the stubshaft E9 is a body member l2, Figure 21. The bodymember l'I2 is providedwith a cutout or trackway i3 for a puri lil pose to Abe laterdescribed.-Slidably or adjusta'bly mounted in the trackway I are three jb-l'ochs"M, 'I5 and l5, Figures 14, 155,- 1S and 1'7. The block 'I4 serves as asupport foro'ne of the eye ,piece mirrors 58, while the block l'serve'sesta support for the other eye piece mirror 53. A means vis provided forcausing if'noveinent of the pair of blocks Ill and 'I5 toward and 'awayfrom each other to i'fhereby move the veye piece mirrors 68 toward andaway `-frorneach other. 'This means comprises a screw member 'l1 whichhas a knurled knob i3 thereon for rotating the rscrew member 17, Figure16. The screw 4member H includes a threaded portion lil which -i'sarranged in engagei ment with the threaded bore ABti that is vformed inthe block T4, and the screw member l'l' .further includes a secondthreaded portion 8I which' has threads that extend in the oppositeydirection from the threads onthe portion l 91. The threaded portion 3lis arranged in threaded engagement With a threaded bore -82 vthat isformed in the block i6. Thus, by rotating the screw member 11, theblocks 74 will :be moved towardand away from each other.. The screwmember il further includes a smooth portion'SS which:entends rotatablythrough a smooth bore 84 in the block lli.

A means is provided for causing movement of the pair of eye piecemirrors t8 from one .side to the other simultaneously. rlhis last-'namedmeans comprises a screw membere Which'has l'a Ylrnurled rotating knob S6mounted on 'one 4en'd thereof.

The screw member -85 includes `a smooth portion 8l that rotatablyprojects through a smooth bore 88 in the block TS, and the 'screwJmonomer -85 further includes a threaded portion 89 that is arranged inthreaded engagement with a threaded bore 9i] in the 'block 15. Byrotating the `screw member by means of the knob 85, the block T5 can be'shifted along the trackvvay 13,and this in turn will result in or causeboth -of the blocks 'I4 and 'I-E to move `in the `saine ldirection atthe same time, so that the eyepiece mirrors 68 will have correspondingmovements.

'The mounting for the eye Vpiece.-mirors G3 further 4includes Yabodypiece QI which has a flange 92 secured theretdthere being an adjustingscrew 93 extending through the .flange 92.- .A hook 9B projects from theange192, and a coilspring Q5 isadapted tcihave one end connected tothehook 64 and the other end connected to a support piece 9S, Figure 19.A stein 'l projects through the body piece QI, Figure 1'7, and intoengagement with a conically-shaped seat 95 so as to insure that theparts are properly centered. Projecting from the support piece 96 is arib- IDU, and the rib Ill-B is adapted to seat in a longitudinallyextending recess or groove IUI, the groove IUI bei-ng formed in the rearsurface of the mirrorholding piece ft2. A hook QG extends from thesupport piece 56, and the other end of the coil spring S5 is adapted tobe connected to the hook 59. The coil spring S5 serves to maintain thepieces 9i and 96 connected together. A pair of spaced angle irons w3 aresecured to the piece m2 .by .suitable .securing elements, such as screwsIM, Figure 20., and the eye piece mirrorA 68 is frictionally heldbetween the pair of angle irons iii. .Suitable screws IE5 extend throughthe piece EQ2 and into engagement with the piece S6 for maintaining thepieces 9B and IZ connected together. Suitable securing elements, such asscrews iti, are 'provided forati-aching the body pieces 9i to the blocksi4 and 1t.

Supported. by each or" the arms i2 is a table assembly i its. The tableassemblies IGS are identical, so that a description of one will sprecofor both. 'The table assemblies Iii are adapted to each support anaerial photograph i?, 'F'igu're i, thereon. nach ci the table'assemblies its iiicluses a horiscntally disposed shelf lo@ which issecured to the arms l2 by a screw Ilm, Figure i1, and the shelves itsare each provided with a track iii. A base H2 is sliably cr adiustablymounted in each of the tracks iii. Projecting upwardly from the base H2is a pair of spaced, parallel, vertically 'disposed side walls 1111'.which are 69201-1 pli/ded with fal'cllale tICk I15'OT a) purpose to belater described. Arranged 4above the base II2 is a table top I I6 upon'which the photo is supported, and carried by the ktable tops H6 is acenter piece II?. A pin or rivet I`I8 provides `a pivotal connectionwhereby the table top l l5 can pivot about a vertical axis. A manna allyoperable means is provided for causing pivotal movement of the tale topsH5 about an axis extending through the `pin IIB, and this meanscomprises a screw member H9, Figure 1-0. The inner end of the screwmember I I9 abuts or contacts the lug 20, the lug 52) being operativelyconnected to the table top. A coil spring .I.2I serve to normally urgethe table top I I6 in a direction so that the lug l2t contacts the innerend of the screw member H9, whereby upon proper rotation of the screwmember I I9, the table top IIS can be pivoted.

A means is provided for tilting or rocking the table top H6, as shown inFigure 12, so that the table top lib lcan be tilted about a horizontalaxis or move from the solid line position shown in Fig'iue 12 to thebroken line position, and vice versa. This means comprises a pair ofspaced, parallel, 'vertically disposed side Vpieces IEE, Iiigure 11, andthe vside pieces |22 depend from the bottoms of the table tops i I8. TheloWe'r surface of each or the side pieces 'Ili2 is 'shaped 'to deine atongue E23 which is arcuateand 'the tongue I 23 rides in or engages inthe traclways 'IIS which are formed in the upper surfaces of the sidewalls II 4. For manually causing the tilting of the table top IIS, ascrew member IZA extends through a bracket |26 which depends from thetable top I IG. A knurledkncb -If25 is mounted onthe endA of the screw4member i213 forrotating the latter. The screw member Ine-extendsthrough, or is arranged in' engagement .with'a nut |21, and the nut |21is pivotally connected to a frame |28 by pins |29, Figure 12. The frame|28 is connected to the base ||2 by a suitable pin or screw |30. Thus,when the screw member |24 is rotated by means of the knob |25, thearcuate shape of the tongues and trackways will cause the table tops ||6to tilt or move into and out of the broken line position shown in Figure12.

The base I |2 is normally maintained immobile in the trackway I I I,Figure 13, by spring-pressed plungers 3|. Thus, a pair of housings |32are mounted in the shelves |09, and a plunger I3| is y slidably arrangedin each of the housings |32, A spring |33 normally urges the plunger |3|into engagement with the adjacent side ofthe base 2, whereby accidentalmovement of the base ||2 is prevented. However, the springs |33`aresufficiently resilient so that when pressure is-appliedto the base H2,it will move in the trackway For causingsliding movement of the base||2,V a screw member |34 extends ,througha bracket |31 which is securedto the shelf |69.v -A pair of knobs 35 and |35 are mountedon the ends ofthe screw member |34, andthe screw member |34 threadedly vengages theside walls 'I I4 which project upwardly from the base |12. Thus, byrotating either the knob |35 or the knob |36, the base ||2 moves in thetrackway |||,so that the table tops H6- can be moved toward andVawayfrom each other, there being two'ofthe'table-tops ||6. Theapparatus of the present invention further comprises a mechanism thatincludes a combination tracing instrument and light source, thismechanism being indicated generally by the numeral |38, Figures 5, 6, 7,8 and 9. -This mechanism includes a horizontally disposed tray |39 thatis rotatably or movably supported onball bearings |40', wherebythe tray|39 can be moved to any desired location. Projecting upwardly from thetray |39 is a pair of spaced, parallel, vertically disposed uprights|46. One of the uprights |40 is provided with a scale or indicia |4|thereon, Figure 5, so that the user will be able to determine thecorrect elevation for the light source. Arranged between the pair ofuprights |40 and extending upwardly from the tray |39 is a threadedshaft or screw member |42, Figure 8. A horizontally disposed ledge |43is movably or adjustably connected to the screw member 42, and the ledge|43 is provided with a shoulder |44 which threadedly engages the screwmember |42. The screw member |42 is provided with a knurled knob |45whereby the screw member |42 can be rotated in order to raise or lowerthe ledge |43. A bearing assembly |46 is arrangedin the lower end of thescrew member |42, whereby Vthe screw member is rotatably connected tothe tray |36. A horizontally disposed plate |41 extends across'the upperends of the uprights |40 and screw member |42, and is connected thereto.A clamp |46, Figure 7, is supported on the plate |41. and the clamp |46carries a set screw |49 which can be tightened or loosened in order tohold the screw member |42 immobile in its various adjusted positions.Supported on the ledge |43 and secured thereto in any suitable manner isa housing |59, there being a light bulb |5| arranged in the housing |50.The light bulb |5| is adapted to be connected -to a suitable source ofelectrical energy by means of wires |52, Figure 8. The light fromthe'bulb 5| is emitted through orpas'se'sthrough -an aperture |53 whichis arl.. un

ranged in the top of the housing |50, and the aperture |53 registerswith an aperture |54 which is formed or arranged in a disc |55. The disc|55 serves to prevent the user from being distracted by the partstherebelow. A suitable prism |56 is also supported on the ledge |43, andby looking through the prism or magnifying glass |56, the user vwill beable to readily observe the markings on the scale |4| so that the userwill know when the light source is located at the proper elevation.

'Ihe tracing instrument which is carried by the tray |39 includes apencil |51 which is provided with a point |58 for marking contours orother lines onV the map being made. The pencil |51 further includes anupwardly extending stem |59 that has a collar |59 secured thereto,Figure 8. A nger |6| has one of its bifurcated ends ar- Yranged inengagement with the bottom of the collar |60, and the finger 6| ispivotally connected to an ear |62 by a pin |63. The other end of thefinger |6| is adapted to be engaged in a spring member |64, the springmember |64 being secured to the trav|39 and serving to maintain thepencil immobile in its various positions. A U-shaped plate |65 issecured to the tray |39 by suitable screws |66, Figure 9, and asupporting member |61 which carries the pencil |51 is positioned betweenthe legs of the plate |65. Suitable set screws |68 are projected throughthe legs of the plate |65 into engagement with the support member |61,whereby the pencil |51 can be furtheradiusted as desired. By exerting adownwardly directed pressure on the top of the stem |59, a mark can bemade by the pencil point |56 on the map being made. In use. referring toFigurel, a suitable pair of aerial photographs are supported on thetable topsA H6. Then, the leg assemblies 43 are adjusted to the properelevation, and the table tops ||6 are adjusted as previously described.Next, the eve piece mirrors 63, which are both transparent and are goodreiiectors, are adjusted, and the mirrors 64 are adjusted. Then, themechanism |38 is moved on the ball bearings to the proper position onthe map to be made, and the light bulb |5| is energized. The scale |4|enables the user to ascertain when the light bulb |5| is at the properelevation. Next, the user positions himself so that his pair `of eyes Elook down through the eye piece mirrors 68, as shown in Figure 1. Thelight shines up through the registering |53 and |54 and the lighttravels the paths indicated by broken lines in Figure 1. The mirrors 68serve to reect part of the light onto and from the mirrors 64, and whenthe properposition is determined, the stem |59 is manually depressed tothereby ycause the point I 58 to'make a mark on the map being made.

From the foregoingit is apparent that an apparatus or machine has beenprovided wherein a person can view one photograph of a stereoscopic pairof photographs of an area and vobject with one eye and also view theother photograph of the stereoscopic pair of photographs with the othereye. All adjustments can bemade so as to provide a parallax free virtualstereoscopic model of the area orobject in the same perspective positionas the actual area and object. The light or dot will appear to float inthe virtual model, and it can be set at a given height with respect tothe model andmade to trace a contour line (line of equal elevation). Or,the light or dot can be varied in height with respect to the virtualstereo model to appear at the surface of the model while traversingplanimetrcfeatures, such as roads,

7 creeks and. the like, The apparatus or the presient Iinventionis'constructed `so that a smallV light or dot appears suspended withina'virtual Astereoscopre model, 4so that contour 'maps can-be made :fromaerial photographs. When 'making a map, laerial photographs having notless tha-n4@ %y overv'lap with a scale distance between photo centers orthep-rincipal points of each photo-not to exceed the averageinterpupillary distance, which is the distance between a persons eyes,and down 4at an Valtitude suitable for the contour vmap yscale 'and`accuracy desired. The aerial photographs are placed so that they willappear as one picture when viewed `with a stereoscope. The model appears to be below or back of the eye piece mirrors 68-and :is imaginary,because the light forming this model is -reectecl from the pictures .onthe .table-tops H5. However, the pin point light or doternit-ted fromthe l-ight'bulb ld is not imag'- -inary, 4in that it Yis actually belowor back -of the eye piece mirrors 5S. The eye piece Vmirrors 68 .aredifferent from most mirrors, in `that they are good reilectors and :arealso transparent. l The degree of reflection and transparency dependslon the relative intensity of the reilected light from the aerialphotographs to the light coming from the bulb 651. The light from thebulb Hit is subdued, and therefore a good, clear, virtual model isformed, but the light shining through the apertures |53 and ld is clearand appears to float within the virtual model. By means of thepreviously-described `adjustmentsa true shape or parallax free andcontrolled model 'as to scale and .relative position to the datum planeis provided. rEhe mirrors 64 can be column-ated, as previouslydescribed, and by alternately closing each eye and viewing the vdot `atthe respective corner positions, the dot should .remain jover the samerespective image point of each photo. If

not, the adjustments Iof the table- -tops I-i' and the eye piece mirrorsE8 are lused to -tip the aerial photos or .adjust them for size untilthe dot coin'- cides with the vsame .image point of the photo when theeyes `are alternately opened and closed.

When this is obtained, the stereo model is in adjustment Afor parallax,but it may not 'b'e in adjustment as to scale or level with the datumplane of the tracing light or dot. This latter adjustment is obtained bytipping the entire in-V strument by the adjustment of the leg assemblies43. This matter adjustment requires at least three survey points ofknown elevation and posi-d tion.

I claim:

l. In an. apparatus for making maps from aerial photographs, ahorizontally disposed table includiing a web and a pair of spacedparallel arms, a plurality of vertically disposed spaced parallel legassemblies for supporting said table, each of said leg assembliescomprising a hollow sleeve having its upper end secured to said table, abushing adjustably mounted in each sleeve and provided witha threadedsocket, a threaded stem arranged in engagement with said socket andhaving a foot on its lower end, a knurled knob secured to said stemadjacent its lower end, a pair of spaced parallel vertically disposedstandards projecting upwardly from said Web and se'- cured thereto, aclamp mounted at the upper end of said standard, a pair of spacedparallel horizontally disposed bars supported by said clamp, a pair ofspaced brackets mounted on said bars, a horizontally disposed posthaving Aa threaded end. arranged in engagement with each Aof saidbrackets and. projectingforwardly therefrom, a

plate connected to each of said posts, a stereoscopic mirror spaced`from said plate and adjustably connected thereto, a stub shaft having athreaded vend arranged in engagement with said clamp and projectingtherefrom, a vertically disposed. body member secured to said stub shaftand provided with a cutout dening a trackway, a first, second and thirdblock slidably arranged in said trackway, said first, second and thirdblocks being arranged for longitudinal movement along said trackway, Aabody piece connected to `each of said rst and third blocks, a support'piece connected to said body piece, a mirrorholdin'g piece connected tosaid support piece, and a .transparent eye piece mirror carried by eachmirror-holding piece, manually operable means vfor shifting saideyepiece mirrors, and a table assembly supported on each of `said arms.

2. The apparatus as described in claim l, wherein said table assemblycomprises a horizontally disposed rectangular shelf lconnected to saidarm and provided with a trackway, a base slidably arranged in saidtrackway, manually operable screw members for causing movement of saidbase in said trackway, and means for causing the table tops on 'thetable assembly to tilt.

`3.y In an apparatus for making maps from aerial photographs, a tableincluding a web and a pair of spaced arms, a plurality of leg assembliesfor supporting said table, each or said leg assemblies comprising ahollow sleeve having its upper end secured to said table, 'a bushingadjustably mounted in each sleeve and provided with 'a socket, a sternarranged in-eng'agement with said socket and having a foot on its lowerend, a knurled knob secured to said stem adjacent its lower end, a pairofi standards projecting upwardly from said web'and secured thereto, aclamp mounted at the upper end of said standard, a pair of bars`supported by said clamp, a pair of spaced brackets mounted on saidbars, 'a post having an en'd arranged in engagement with each of saidbrackets and projecting forwardly therefrom, a plate connected to eachof said posts, a

P body mirror spaced from said plate and adjustably connected thereto, astub shaft having an end arranged in engagement with said clamp andprojecting therefrom, a body member secured to' said stub shaft andprovided- With a cut-out defining a trackway', a rst, second and thirdblock slidably arranged in said trackway, said rst, second and thirdblocks being arranged for longitudinal movement along said trackway, abody piece connected vto each of said first and third blocks, asupport-piece connected to said body piece, a mirror holding piececonnected to SaidV body piece, and a transparent eye piece mir'- rorcarried by each mirror holding piece, manually operable means forshifting said eye piece mirrors, and a table assembly supported on eachof said arms.

NORMAN B. PLA'I'T.

References' Cited in the `ille of this patent UNITED STATES PATENTSNumber Name Date 1,985,066 Von Gruber Dec. 18, 1934 1,999,236 Hess n--Apr. 30, 1935 2,657,921 Santoni r Oct. 20, 1936 2,263,971 King et al. sl Nov. 25, 1941 2,333,643 Cook Nov. 28, 1944 2,451,031 Kelsh ---v nsurnsOct. '12, 1948 2,481,246 rvSchlatter ,.-s Sept. 1949 2,555,106 Beazley..s May 29,1951

